The present invention relates to an automatic stabilizing and reinforcing device for vehicle raising jacks, which is applicable to various types of mechanical vehicle raising jacks, such as "Y" jacks, parallelogram jacks with extended legs and others.
Various types of mechanical vehicle jacks are known.
An "Y" jack has a column having a ground support floor and a raising arm pivotally mounted to the column at an intermediate height thereon and having a generally channel-shaped end stirrup for supporting the vehicle. For this purpose the stirrup has respective flanges in the proximity of the corresponding edges of the underside of the body. The column and the arm are linked together by a screw which is threaded into a nut pivotally connected crosswise to the top of the column, while the front end of the screw is pivotally and rotatably connected to an intermediate point of the raising arm, or the nut could be pivotally arranged on the raising arm and the screw would be pivotally and rotatably attached to the top of the column closed to the rear end thereof. The rear end of the screw is provided with a crank or the like enabling the user to operate the mechanical arm for raising the vehicle and thus be able to replace the corresponding faulty wheel.
A parallelogram jack has four hingedly connected arms and a screw arranged on the diagonal thereof. One of the ends of the screw is threaded in a nut arranged on one of the apexes of the parallelogram, while the other end is attached to the opposite apex, but rotatably. A portion of the screw juts outward for operation by a crank and in the "Y" jack. In this jack the lower apex of the parallelogram has pivotally attached thereto a ground support plate acting as a foot, and the upper apex of the parallelogram has attached thereto another plate acting as a stirrup for supporting the corresponding part of the vehicle.
Another jack has a mechanism with four hingedly connected arms arranged in the form of a parallelogram provided with a screw situated on a diagonal as the above described parallelogram jack, and which is approximately horizontal when the jack is in the position of use. It is operated by a crank or the like. The front end of the screw is threaded in a nut pivotally mounted to the front apex of the parallelogram, while the opposite end of the screw passes through a cross member which is pivotally connected to the rear apex of the parallelogram. The rear end of the screw is terminated in a rear expansion which is rotatably supported against the cross member. A bearing is located preferably intermediately to facilitate the rotary support. The relative position of the rotary support and the nut can be reversed. This jack is provided with a stirrup close to the upper apex of the parallelogram on an extension of the rear upper arm. Characteristically the rear lower arm of the parallelogram extending from the rear apex is extended downwardly forming a jack support leg which is pivotally attached in turn to a ground support foot.
The known jacks of different types provide different advantages making them particularly useful for particular applications in accordance with technical requirements of the manufacturers of the corresponding vehicles. However, there is a general problem with regard to the raising jacks as to their use by normal user who is not specifically versed in this field even in the event of the correct use of the jack to replace a defective wheel of a vehicle. This problem consists of ensuring the stability of the structure formed by the jack and the vehicle when the jack is being used, and also of withstanding mechanical effort required by the vehicle manufacturer in corresponding conditions.
It is known that mechanical jacks for raising vehicles have a support for the underside of the vehicle to be raised. The support is known as an above mentioned stirrup and in some cases it is fixed, i.e. is firmly attached to the end of the bearing arm and in other cases it is pivotally mounted about a horizontal pin at the end of the arm which forms the pivot pin for the stirrup for better adaptation to the vehicle body during lifting and lowering operations with the mechanical jack. When the stirrup rotates relative to the bearing arm about a pivot pin which is parallel to the axis of pivoting of the arm, it is known to arrange the pivot pin at a certain distance from the support plane of the vehicle body. In accordance with a further embodiment the pivot point is supported directly alongside the underside of a first support portion with the stirrup so that the distance between the pivot point and the lower surface of the vehicle body is determined only by the thickness of the stirrup portion.
The known stirrups are normally provided, in addition to the flat portion, with a "U" or "V" shaped recess or channel in which a lower flange on the underside of the vehicle body, reinforced to withstand the mechanical stress resulting from being supported on the jack stirrup while the vehicle is being raised or lowered, may be freely housed. The flange serves to guide the jack stirrup both when being placed below the body and when being raised or lowered and to prevent untimely slipping without it reaching down against the bottom of the stirrup channel.
A "Y" type vehicle raising jack is disclosed in the Utility Model number 247,051, in which the pivot pin of the support plate or stirrup bears directly against the lower side thereof and is arranged approximately horizontally with the projecting formation of the vehicle body floor, i.e. of the underside of the vehicle body where the jack stirrup is placed and adjusted.
A jack having a stirrup pivotally mounted on the end of the bearing arm, by way of a pivot pin parallel to the axis of pivoting, may adapt itself better to the relative movement between the vehicle body and said jack, than in the case of a jack having its stirrup fixed relative to the bearing arm thereof. Nevertheless, there are vehicles today where the simple rotation of the jack relative to the bearing arm thereof is not sufficient for the specific suspension, which at times even has a differentiated behavior between the front wheel suspension and the rear wheel suspension of said vehicles, but rather they require the stirrup to have various degrees of freedom, i.e., various movements to be able to adapt itself suitably to the complex movement of said vehicles when they are being raised or lowered with a mechanical jack, because the suspension gives way in one or another direction other than the one imposed by the mere rotation about a transverse axis relative to the stirrup bearing arm. Furthermore, the vehicle manufacturers require the jacks to be mechanically stronger, partly because of the greater weight of such vehicles derived from the increase of their passive safety (body reinforcement, internal complements, etc.). It implies a corresponding reinforcement of the parts of interest of the jack, which is not achieved with the known jacks, unless on the basis of increasing the weight thereof excessively, with a corresponding increase in cost.
A stabilizing and reinforcing device for vehicle raising jacks is proposed by the applicant in the Utility Model number 9,300,303. The device disclosed there has an arm provided at the end thereof with a stirrup for supporting the vehicle and having the form of a transverse channel with at least a flat front support portion, an arm or column to which the jack foot is pivotally connected and a nut in which the jack screw is threaded. This device is characterized in that the stirrup is provided, at the front support portion thereof, with three downwardly directed projections, one in the center and the other equidistant therefrom, transversely aligned close to the channel and spaced apart from the respective side edges of said front support portion of the stirrup. The projections bear against a transverse rod of a length slightly greater than the spacing between the two equidistant projections and attached to the end of the stirrup bearing arm. The latter has attached thereto a central plate member of a width slightly smaller than the spacing between the two upright walls of the end of the bearing arm and has two facing parallel plates, connected by an intermediate plate, forming a lower tubular central portion situated before the front wall of the stirrup channel and under the front support portion, determining a central recess by which said stirrup if freely pivotally connected to the rod, with a substantial clearance. The stirrup channel is provided with a center front cutout tab which is directed downwardly and to which there is attached the lower portion of the plate member, also directed downwardly and arranged below the recess. There is attached to said lower portion of the plate member the end of a central spring, the opposite end of which is attached to the stirrup bearing arm, keeping the latter centered against the rod in a preset position. The foot is provided with a central recess in which there is located the corresponding lower portion of the arm or column carrying the foot. The recess is crossed, just above, by a transverse rod attached at the front end thereof to the foot and to which the arm is pivotally connected, a spring being disposed between the foot and arm.
The device provides, among others, the advantages of increasing the degree of stability of the jack, reinforcing it at mechanically critical parts thereof and making it easier for the user initially to install the jack under the vehicle body.